U.S. patent number 8,535,389 [Application Number 12/914,339] was granted by the patent office on 2013-09-17 for prosthetic socket liner.
This patent grant is currently assigned to McKinney Prosthetics. The grantee listed for this patent is Donald Ray McKinney. Invention is credited to Donald Ray McKinney.
United States Patent |
8,535,389 |
McKinney |
September 17, 2013 |
Prosthetic socket liner
Abstract
A removable liner used in conjunction with a socket for a
prosthetic device, in which a vacuum is wicked across the entire
area of a porous fabric of the liner, is disclosed. The liner
preferably includes a shaped-layer made from one of either a
silicone or a urethane and has an exterior surface, an interior
surface and a passage therein which opens at each of the two
surfaces and connects to a valve of the socket. The liner further
includes a first porous fabric covering at least a portion of the
exterior surface of the shaped-layer including the corresponding
opening of the passage, and a second porous fabric covering at
least a portion of the interior surface of the shaped-layer
including the corresponding opening of the passage. A vacuum source
coupled to the liner, via the valve on the socket, draws a vacuum
which is wicked across the entire surface of the first and second
porous fabrics which interface with the socket and the user's
residual limb, respectively. The vacuum secures the socket to the
liner and the liner to the residual limb of the user.
Inventors: |
McKinney; Donald Ray (Gurnee,
IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
McKinney; Donald Ray |
Gurnee |
IL |
US |
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Assignee: |
McKinney Prosthetics (Gurnee,
IL)
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Family
ID: |
43757317 |
Appl.
No.: |
12/914,339 |
Filed: |
October 28, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110071649 A1 |
Mar 24, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12586235 |
Sep 18, 2009 |
8282686 |
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Current U.S.
Class: |
623/34;
623/36 |
Current CPC
Class: |
A61F
2/7812 (20130101); A61F 2/80 (20130101); A61F
2002/805 (20130101) |
Current International
Class: |
A61F
2/80 (20060101); A61F 2/78 (20060101) |
Field of
Search: |
;623/33,34,36,37 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10 2006 045 517 |
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Apr 2008 |
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DE |
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Other References
US. Appl. No. 61/207,876, filed Jun. 10, 2008. cited by examiner
.
English language translation of Mushenko et al., SU 1739990 A (Jun.
15, 1992). cited by examiner.
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Primary Examiner: Willse; David H
Attorney, Agent or Firm: Bishop Diehl & Lee, Ltd.
Parent Case Text
RELATED APPLICATIONS
This application is a continuation-in-part and claims the priority
of U.S. application Ser. No. 12/586,235, titled "Prosthetic Socket"
and filed on Sep. 18, 2009, now U.S. Pat. No. 8,282,686. The
present application also incorporates by reference the disclosures
of U.S. application Ser. Nos. 11/640,150, filed Dec. 14, 2006, Ser.
No. 12/286,474, filed Sep. 30, 2008, and 61/192,386, filed Sep. 9,
2008.
Claims
What is claimed is:
1. A liner for a socket of a prosthetic limb which is to be
attached to a residual limb having at least one surface area
unsuitable for application of vacuum pressure, the liner
comprising: a shaped-layer comprised of one of either a silicone or
a urethane and having an exterior surface, an interior surface and
a passage therein which opens at each of the two surfaces; a first
porous fabric covering at least a portion of the exterior surface
of the shaped-layer including covering the corresponding opening of
the passage; and a second porous fabric which directly contacts the
residual limb during use, the second porous fabric covering the
interior surface of the shaped-layer including covering the
corresponding opening of the passage wherein the second porous
fabric includes at least one cut-out portion which corresponds to
the at least one surface area of the residual limb unsuitable for
application of vacuum pressure; wherein, during use a negative
pressure is maintained across the portion of the exterior surface
covered by the first porous fabric and the interior surface covered
by the second porous fabric excluding the cut-out portion when a
vacuum source is coupled to the passage of the shaped-layer.
2. The liner of claim 1, wherein the first porous fabric and the
second porous fabric are of the same material.
3. The liner of claim 2, wherein the material of the first and
second porous fabric is cotton.
4. The liner of claim 2, wherein the material of the first and
second porous fabric is polyester.
5. The liner of claim 2, wherein the material of the first and
second porous fabric is a cotton/polyester blend.
6. The liner of claim 1, wherein the first porous fabric interfaces
with a prosthetic socket during use.
7. A liner-socket combination for use with a prosthetic device
which is to be attached to a residual limb having at least one
surface area unsuitable for application of vacuum pressure, the
combination comprising: a socket formed to fit the residual limb of
a user and having a prosthetic device attached thereto; a vacuum
source coupled to a valve seated in a sidewall of the socket; and a
liner detachably positioned within the socket and comprising: a
shaped-layer comprised of one of either a silicone or a urethane
and having an exterior surface, an interior surface and a passage
therein which opens at each of the two surfaces; a first porous
fabric covering at least a portion of the exterior surface of the
shaped-layer including the corresponding opening of the passage;
and a second porous fabric which directly contacts the residual
limb during use, the second porous fabric covering the interior
surface of the shaped-layer including the corresponding opening of
the passage wherein the second porous fabric includes at least one
cut-out portion corresponding to the at least one surface area of
the residual limb unsuitable for application of vacuum pressure;
wherein, during use a negative pressure is maintained across the
portion of the exterior surface covered by the first porous fabric
and the interior surface covered by the second porous fabric
excluding the cut-out portion when the vacuum source is coupled to
the passage of the shaped-layer via the valve.
8. The liner-socket combination of claim 7, wherein the first
porous fabric interfaces with an interior surface of the
socket.
9. The liner-socket combination of claim 8, wherein the first
porous fabric is held to the interior surface of the socket during
use by the creation of a negative pressure.
10. The liner-socket combination of claim 7, wherein the first
porous fabric and the second porous fabric are of the same
material.
11. The liner of claim 10, wherein the material of the first and
second porous fabric is cotton.
12. The liner of claim 10, wherein the material of the first and
second porous fabric is polyester.
13. The liner of claim 10, wherein the material of the first and
second porous fabric is a cotton/polyester blend.
14. A method for securing a prosthetic device to a residual limb of
a user, the residual limb having at least one surface area
unsuitable for application of a vacuum, the method comprising the
steps of: forming a socket to fit properly to a desired residual
limb, the socket having a cavity and a valve; positioning a liner
within the cavity of the socket, the liner comprising: a
shaped-layer comprised of one of either a silicone or a urethane
and having an exterior surface, an interior surface and a passage
therein which opens at each of the two surfaces and configured to
connect to the valve of the socket; a first porous fabric covering
at least a portion of the exterior surface of the shaped-layer
including the corresponding opening of the passage; and a second
porous fabric which directly contacts the residual limb during use,
the second porous fabric covering the interior surface of the
shaped-layer including covering the corresponding opening of the
passage wherein the second porous fabric includes at least one
cut-out portion which corresponds to the at least one surface area
of the residual limb unsuitable for application of vacuum pressure;
connecting a vacuum source to the valve of the socket; and drawing
a vacuum to create a negative pressure across the portion of the
exterior surface covered by the first porous fabric and the
interior surface covered by the second porous fabric excluding the
cut-out portion such that the liner is held to an interior surface
of the socket and an exterior surface of a residual limb.
Description
TECHNICAL FIELD OF THE INVENTION
The present device relates to vacuum liner used in a socket
assembly for a prosthetic device. In particular, the present device
relates to a vacuum-mapped liner which resides within a socket
assembly having an outer shell and an air barb communicating with
the liner on the interior of the socket and for connection to an
exterior vacuum source.
BACKGROUND OF THE INVENTION
The history of artificial limbs goes back to very remote times. In
fact, there is some evidence that the Romans and the Greeks may
have improvised some sort of substitute for limbs lost as a result
of battles and the vicissitudes of life. Herodotus tells us of a
prisoner who amputated his own foot in order to free himself from
the shackle, after which he escaped and returned to his friends,
who made a wooden foot.
The treasure trove that turned up at Capua in 1885 in a tufa tomb
is probably the most valuable and indisputable evidence that
artificial legs were made in early times. The relic is now on
exhibition in the Museum of the Royal College of Surgeons, London.
The official catalogue describes it thus: "Roman artificial leg;
the artificial limb accurately represents the form of the leg. It
is made with pieces of thin bronze, fastened by bronze nails to a
wooden core. Two iron bars, having holes at their free ends, are
attached to the upper extremity of the bronze. A quadrilateral
piece of iron, found near the position of the foot, is thought to
have given strength to it. There was no trace of the foot, and the
wooden core had nearly crumbled away."
From those early times to about the beginning of the 20th century,
little or no advance was made in the art; and, as no evidence
exists to prove to the contrary, it is quite reasonable to suppose
that for many centuries the manufacture of artificial limbs was one
of the lost arts.
In the early part of the 20th century, the Duke of Anglesea, being
in need of an artificial leg, and possessing an inventive faculty,
suggested to an English instrument maker what proved to be a very
answerable substitute, a decided improvement on the primitive peg
of the doughty Peter. The leg received but little improvement until
the venturesome Selpho introduced it into this country with some
admirable modifications of his own; here it met with American
enterprise and began to thrive.
Typically, artificial limbs are held in place by a series of straps
or some type of suspension system. Some are suspended with a
silicone sleeve that has a pin that locks in place.
The earliest use of a vacuum to attach an artificial leg was with
above the knee amputees using what is known as a suction socket.
The "suction socket" uses the same principle as a suction cup where
the maximum strength of the force holding the objects together is a
function of the atmospheric pressure at the altitude of use. In
artificial leg usage the suction or vacuum is reduced by the vapor
pressure of the sweat at the internal temperature of the socket.
Use of suction sockets on below knee amputees was not initially
practical. The next advance in using vacuum was the introduction of
the Harmony system which uses a mechanical pump operated by the
energy of walking Each step operates a pump.
A vacuum system improves the fit and comfort between the device and
the residual limb. A vacuum pump forces out air through a one-way
valve, creating negative pressure with every step the patient
takes. A tiny tube connects the pump to a weight-bearing socket
which is enveloped in a urethane liner or sleeve. By improving
suspension, the prosthesis offers better control and less pressure
on the limb and liner. The pump is powered by the wearer's body
weight. Taking a step compresses the device, which creates the
vacuum between the liner and the socket.
Through the years, many socket structures have been developed for
use with vacuum and non-vacuum systems alike. Many of these
structures are represented in the patent literature. For example,
U.S. Pat. No. 2,634,424 to O'Gorman discloses a double-walled
socket of resiliently flexible material.
U.S. Pat. No. 5,007,937 to Fishman deals with a structure for
enhanced retention of artificial limbs and method of fabrication in
which an air impermeable sealing band of rubberized material is
introduced between the patient's stump and the interior of a
stump-receiving socket of an artificial limb, in one of two ways,
depending on whether or not the patient wears a stump sock. If the
patient wears a stump sock, the band of sealant material is
impregnated into the stump sock. If the patient does not wear a
stump sock, an impregnated sock is incorporated into the interior
structure of the socket of the patient's prosthesis. The
impregnated sock itself is fabricated by placing a conventional
stump sock on a somewhat oversized form. An appropriate annular
region on the sock is then masked off by means of tightly fitting
plastic bags, and one of the plastic bags provides an enclosing
outer sheath which encompasses the annular region and extends
upwardly above the form. A rubberized material in liquid form is
introduced through the top of the outer sheath and a vacuum is
introduced below to draw the material into the annular region of
the sock, so as top impregnate the same. The rubberized material
penetrates the sock, is worked into an axially contoured shaped,
and is then permitted to set. A stump-receiving socket for an
artificial limb with an integral annular seal is fabricated by
placing a stump sock with the seal on a cast of a patient's leg and
then laminating the socket over the sock using conventional
procedures for manufacturing stump-receiving sockets.
U.S. Pat. No. 5,108,456 to Coonan shows a prosthetic appliance for
residual limb is disclosed comprising a prosthesis member having a
cavity defined by side walls formed of a rigid molded material. A
separate removable molded socket member formed of a flexible
material is nested within cavity of the prosthesis member and is
adapted to receive the residual limb. Several separate,
independently inflatable bladders preferably attached to the
exterior of the socket member, when inflated, act against the rigid
side walls of the prosthesis member to resiliently force discrete
portions of the socket member side walls inwardly to grip the
residual limb. An inflation control means is provided in the form
of at least one manually operable air pump and one or more manually
operable air valves, one for each of said bladders, for selectively
inflating the associated bladder separately and independently from
the other bladders, so that the gripping pressure of the residual
limb at each discrete portion of the socket member may be adjusted
separately and independently by both the air pump and the air
valves.
U.S. Pat. No. 5,156,629 to Shane is directed to a removable and
adjustable prosthetic insert disposed between the stump of a limb
and the socket of a prosthesis is comprised of a high strength,
pliable polymeric material within which are formed a plurality of
spaced air pockets, or voids, which are coupled together by a
series of connecting channels, or passages. Using an air valve
extending through the polymeric material and coupled to the closed
air pocket/channel system, the air pockets may be inflated to fill
the stump/socket inter-space and provide a tight-fitting, air
cushioned prosthetic socket attachment. The air inflatable
prosthetic insert can accommodate changes in the condition of the
stump and applies a uniform prosthetic attaching force thereto.
Other embodiments also employ an inflatable air cushion and make
use of spaced, solid spheres disposed between air passages arranged
in a grid-like array; and pinched tubing with interconnecting air
passages to form a series of inflatable nodules. An air cushion
isolates the limb stump from the hard, rigid prosthesis socket for
user comfort and provides a custom fit for improved control and
maneuverability of the prosthetic device.
U.S. Pat. No. 5,139,523 to Paton discusses an apparatus for
mounting a socket above the knee of an amputee, wherein the socket
is arranged for mounting a prosthesis to a lower terminal end
thereof. The sleeve includes an internal cage formed of rigid rods,
including hook members imbedded within a semi-spherical sleeve
support, with the cage encased in a polymeric covering. A vent is
provided through the sleeve support for venting interiorly of the
socket. The socket may further include pneumatic chambers for
enhanced comfort in support of the socket.
U.S. Pat. No. 5,888,231 to Sandvig describes a method of preparing
a breathable, custom-molded liner for an artificial limb socket
includes the steps of providing a liner comprising an open-celled
foam material impregnated with a curable resin, activating the
curable resin, and deforming the foam material by positioning a
residual limb on one of opposing surfaces of the liner, and
positioning the artificial limb socket on a second opposing surface
of the liner until curing is substantially complete to create and
retain an impression of the residual limb in the foam material. A
liner blank useful for preparing an artificial limb socket,
comprising a foam material impregnated with a curable resin and
sewn into the shape of a sock for an artificial limb, is also
described.
U.S. Pat. No. 6,585,774 to Dean involves a dynamic variable
geometry prosthetic fitting system with fluid-filled bladders and
automatically regulating their volumes to provide a continuously
secure fit. This system can vary volume continuously to accommodate
natural variation in an amputee's residuum. It makes reliable
suction retention of a prosthesis easier for the prosthetist to
achieve while reducing the potential for tissue lesions. By
maintaining a continuous, secure fit, the amputee's sense of
confidence and willingness to use the prosthesis increases.
U.S. Pat. No. 6,926,742 to Caspers is directed to a
hypobarically-controlled artificial limb for amputees includes a
single socket with a volume and shape to receive a substantial
portion of the residual limb. A liner with a volume less than the
residual limb is donned over the residual limb, with the liner
tensioned into a total contact relationship with the residual limb.
A sealed cavity is formed between the socket and the liner. A
vacuum source is connected to the socket cavity thereby drawing the
residual limb and liner into firm and total contact with the
socket. To compensate for some air leakage past the seal, there is
a mechanism to maintain the vacuum in the cavity. A plate/socket
attachment connects the vacuum source to the cavity.
Among the disadvantages of known systems are size, weight, and
difficulty of use. There are many amputees that cannot use known
systems because of size (particularly smaller adults and children),
age of the patient, and length of the stump. For many patients, the
time-consuming steps and cumbersome strap systems involved in using
known prostheses cause the patients to eschew prostheses entirely.
Further, known sockets are subject to unhygienic conditions, as
they collect perspiration from the residual limb, and bacteria and
other contaminants from the ambient air surrounding the
prosthesis.
It can thus be seen from the foregoing that the need exists for a
prosthetic socket that ameliorates the drawbacks of known devices,
while remaining easy-to-use, lightweight, and hygienic.
These together with other objects of the invention, along with the
various features of novelty which characterize the invention are
pointed out with particularity in the claims annexed to and forming
a part of this disclosure. For a better understanding of the
invention, its operating advantages and the specific objects
attained by its uses, reference should be had to the accompanying
drawings and descriptive matter in which there is illustrated
embodiments of the invention.
SUMMARY OF THE INVENTION
Generally, a socket assembly for use with a prosthetic device for
hygienically and comfortably securing a prosthetic to a residual
limb for attachment to a vacuum source is disclosed and claimed.
The socket assembly comprises an outer shell capable of receiving a
residual limb, a skin interface secured to at least a portion of
the interior of the outer shell, and an air barb for communication
between the interior and the exterior of the socket. In an aspect
of an embodiment, the air barb may be connected to a vacuum source
for evenly distributing the force through the skin interface. An
aspect of an embodiment of the present device includes that the
skin interface is vacuum-permeable.
An additional embodiment of the present device is provided in which
the socket assembly further comprises a high-vacuum valve for
communicating between the interior and the exterior of the socket
assembly. In an embodiment of the device, a diffusion pillow is
provided between the intake of the air barb and the interior of the
socket assembly, where the diffusion pillow may comprise a
synthetic fiber pillow. An aspect of an embodiment of the socket
assembly provides that the outer shell is fabricated from plastic,
such as thermoformable plastic, or from PETG.
In another aspect of an embodiment, the skin interface may be
fabricated from a textile material, including a three-ply textile
material such as a synthetic textile material, or from wool. Yet
another aspect of an embodiment of the disclosed socket assembly is
that it further comprises an annular vacuum seal secured to the
interior of the socket assembly, one aspect of the annular vacuum
seal being that it may be formed from urethane or silicone. In an
additional embodiment, the skin interface extends over
substantially all of the interior of the socket and further
comprises an annular band extending over a portion of the interior
of the socket.
In still another embodiment, a removable liner may be used in
conjunction with the socket. The liner is preferably comprised of a
shaped-layer made from one of either a silicone or a urethane and
having an exterior surface, an interior surface and a passage
therein which opens at each of the two surfaces and connects to a
valve of the socket. The liner further includes a first porous
fabric covering at least a portion of the exterior surface of the
shaped-layer including the corresponding opening of the passage,
and a second porous fabric covering at least a portion of the
interior surface of the shaped-layer including the corresponding
opening of the passage. A vacuum source coupled to the liner, via
the valve on the socket, draws a vacuum which is wicked across the
entire surface of the first and second porous fabrics which
interface with the socket and the user's residual limb,
respectively. The vacuum secures the socket to the liner and the
liner to the residual limb of the user.
These and other aspects of the invention may be understood more
readily from the following description and the appended
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are illustrated by way of example, and
not by way of limitation, in the figures of the accompanying
drawings and in which like reference numerals refer to similar
elements and in which:
FIG. 1 is a perspective view of an embodiment of a socket assembly
in accordance with the principles of the present invention;
FIG. 2 is a cross-sectional view taken generally along the plane
parallel to line II-II of FIG. 1;
FIG. 3 is a side view of one embodiment of a liner made in
accordance with the present invention;
FIG. 4 is a cross-section of the embodiment of FIG. 3;
FIG. 5 is a side view of one embodiment of a liner made in
accordance with the present invention;
FIG. 6 is a cross-section of the embodiment of FIG. 5; and
FIG. 7 is a cross-section of an embodiment of the present invention
illustrating "mapping" of an internal fabric.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the following description, specific details are set forth in
order to provide a thorough understanding of the invention.
However, it will be apparent that the invention may be practiced
without these specific details.
While this invention has been described in connection with the best
mode presently contemplated by the inventor for carrying out his
invention, the preferred embodiments described and shown are for
purposes of illustration only, and are not to be construed as
constituting any limitations of the invention. Modifications will
be obvious to those skilled in the art, and all modifications that
do not depart from the spirit of the invention are intended to be
included within the scope of the appended claims. Those skilled in
the art will appreciate that the conception upon which this
disclosure is based, may readily be utilized as a basis for the
designing of other structures, methods and systems for carrying out
the several purposes of the present invention. It is important,
therefore, that the claims be regarded as including such equivalent
constructions insofar as they do not depart from the spirit and
scope of the present invention.
The invention resides not in any one of these features per se, but
rather in the particular combinations of some or all of them herein
disclosed and claimed and it is distinguished from the prior art in
these particular combinations of some or all of its structures for
the functions specified.
FIGS. 1 and 2 illustrate a socket assembly 10 in accordance with
the principles of the present invention. The socket assembly 10 is
suitable for use with any vacuum-assisted prosthetic system, but
finds particular utility with the systems claimed and described in
U.S. Ser. No. 11/640,150 and U.S. Ser. No. 12/286,474, the
specifications of which are incorporated by reference herein. The
socket assembly 10 includes an outer shell 12 fabricated from an
airtight and relatively rigid material. The outer shell material
must be capable of being thermoformed or vacuum-formed over a
plaster mold cast from a residual limb to conform to the residual
limb of the amputee to which the prosthesis is fitted. It is
contemplated that a variety of thermoplastic materials will perform
well. Examples of such materials are polyethylene terephthalate,
including PETG manufactured by Kodak and available from a variety
of sources, and NorthPlex, available from Endolite, Inc. of
Centerville, Ohio. The formed shell can be further reinforced using
carbon fiber, Kevlar mat or other reinforcing materials and an
appropriate adhesive system. The reinforcing material may be bonded
to the socket using, e.g., a peroxide-cured thermoset acrylic
polymer or the like.
A skin interface 14 is secured to the interior 16 of the outer
shell 12, for example, by adhesive or integral molding. The skin
interface 14 advantageously covers a majority of the contact area
between the socket assembly 10 and the residual limb of the user.
The skin interface 14 is fabricated from a vacuum-permeable
material, such as a three-ply textile material. It is contemplated
that materials such as wool used in the three-ply sock available
from DAWFLO, or a three-ply synthetic material such as that used in
the KNIT-RITE A-PLUS sock are suitable.
A high-vacuum valve 18 is connected between the interior 16 of the
socket assembly 10 and the exterior 20 of the socket assembly 10.
One example of a suitable valve is available from ESP HV Valve of
Newton, N.J. The high-vacuum valve 18 must be capable of holding
sufficient vacuum to secure the socket assembly 10 to the residual
limb of the user. The amputee pulls tissue into the socket assembly
10 via the high-vacuum valve 18 in a conventional manner. Using a
donning sleeve, the user pulls the residual limb tissue into the
socket and HV valve, then removes the donning sleeve via the HV
valve.
An air barb 22 is secured to the outer shell 12, and includes an
intake communicating with the interior 16 of the socket assembly 10
and an outlet communicating with the exterior 20 of the socket
assembly 10. The air barb 22 is adapted and constructed for
connection to a vacuum system as described in U.S. Ser. No.
11/640,150. The barb 22 is the portal through which air is
evacuated from the interior of the socket assembly 10. One example
of a suitable air barb is available from Clippard Tools of
Cincinnati, Ohio. A diffusion pillow 24 is positioned between the
intake of the air barb 22 and the skin interface 14. The diffusion
pillow 24, which can be fabricated from a nonwoven fabric, for
example, a Dacron felt material such as is available from PEL Inc.
of Cleveland, Ohio, or any other suitable synthetic textile
material. The diffusion pillow 24 is used to diffuse the source of
vacuum, which may generate 24''HG, over a larger area to minimize
the danger of tissue damage.
If desired, an additional vacuum seal 26 can be provided. The
vacuum seal 26 is illustrated as an annular sealing member secured
to the interior 16 of the socket assembly 10 at a location above
the skin interface 14. The vacuum seal 26 is used as a supplemental
vacuum seal for residual limbs with high volume fluctuations, and
can be fabricated from a non-porous material such as urethane or
silicone elastomer. One suitable seal member is an annular sleeve
associated with suspension sleeves, as available from Otto Bock of
Plymouth, Minn.
An alternative embodiment of a socket assembly 10 may provide for
an annular band extending around a portion of the interior of the
shell 16, as is known in the art. With many amputees, the end of
the residual limb is unusually irregular in its topography. The
irregular nature of such residual limbs renders it difficult to
maintain vacuum in known socket assemblies. However, in the present
invention, the vacuum is distributed through the skin interface.
The annular band configuration of the skin interface 14 allows the
contact area, and thus the vacuum distribution, to be limited to
those areas of the residual limb having relatively regular and
smooth surfaces, thus providing sufficient vacuum to retain the
socket on the residual limb.
Selective placement of the skin interface allows the mapping of the
socket to be placed only in those areas of the socket that will be
in contact with portions of the residual limb capable of
maintaining vacuum contact. Thus, areas with extensive scarring
and/or irregular topography can be avoided, while areas with
smoother tissue provide high-vacuum areas. For example, in a stance
(standing) position, the contact portion of the residual limb is
under high vacuum, while the irregular portion is under no vacuum.
In a step (swing) action, the irregular portions of the residual
limb will experience at most 2.5''Hg to 3''Hg, far less than will
cause tissue damage.
The socket assembly 10 of the present invention provides many
advantages over known systems. For example, it is contemplated that
most applications of the socket assembly of the present invention
will weigh on the order of 6 ounces to 2 pounds, and require 1
minute or less to put on. The present invention eliminates the need
for the use of gels or lubricants to prepare the limb.
Significantly, the direct contact of the skin interface with the
limb allows the socket assembly of the present invention to
vaporize perspiration, thus enhancing the comfort level and overall
hygiene of the user. The reduced weight also simplifies the tasks
required by systems that may be associated with the prosthetic
device.
With reference to FIGS. 3-7, another embodiment of the present
invention can be more readily explained. The prosthetic socket of
all previous embodiments may be alternatively equipped with a
detachable liner 30. Liner 30 is comprised of a shaped-layer 32
preferably manufactured from one of either a silicone or a
urethane, as these materials provide the requisite flexibility
needed. A passage 33, which may be positioned anywhere on the liner
30, passes through the shaped-layer 32 and opens at both an
interior surface 34 and an exterior surface 36. The liner 30 is
made complete by the addition of a first porous fabric layer 37
covering at least a portion of the exterior surface of the
shaped-layer 32 and a second porous fabric layer 38 covering at
least a portion of the interior of the shaped-layer 32. In both
layers, 37 and 38, the fabric must cover the surface opening of the
passage 33.
The fabric used for the first and second layers, 37 and 38, is
preferably made of cotton, but may be a synthetic material (e.g.,
polyester) or a blended material (cotton/synthetic). Commercially
available fabrics have been suitable for most applications.
Once the passage 33 is coupled to a vacuum source, the porous
fabric layers, 37 and 38, perform the task of wicking the negative
pressure about their entire surface area. As such, the area of the
vacuum can be controlled by removing the fabric from specific areas
to avoid vacuum pressure contact with damaged tissue or the like.
For example, scarred areas of the residual limb may not have
sufficient viable tissue or an area of the residual limb may
otherwise be inadequate for application of a vacuum. Portions of
the second porous fabric layer 38 corresponding to an injured area
could be cut away, as illustrated in FIG. 7. Accordingly, vacuum
pressure would not be wicked to the injured area. This is known as
"mapping" the liner.
The embodiment illustrated in FIGS. 3 and 4 is best used with
either a double-wall or single-wall socket, while the embodiment of
FIGS. 5 and 6 is used with what is known as a brimless socket.
With respect to the above description, it is to be realized that
the optimum dimensional relationships for the parts of the
invention, including variations in size, materials, shape, form,
function and manner of operation, assembly and use, and all
equivalent relationships to those illustrated in the drawings and
described in the specification, that would be deemed readily
apparent and obvious to one skilled in the art, are intended to be
encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the
principles of the invention. Further, since numerous modifications
and changes will readily occur to those skilled in the art, it is
not desired to limit the invention to the exact construction and
operation shown and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
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